The Philosophy of Hume

The Philosophy of David Hume (1711-1776)

Introduction

• David Hume is known as a radical empiricist and skeptic because of his focus on experience and skepticism toward metaphysical ideas like "substance," "God," "causality," and "self."

• Hume's main empirical principle, from A Treatise on Human Nature, states that an idea cannot be formed without a prior impression. Essentially, no impression, no idea.

• Hume's critique of causality involves analyzing the idea of causality to see if its elements match with an impression.

• Hume's theory of impressions is similar to Locke's.

Hume's Theory of Impressions

Impressions

• Impressions are vivid perceptions, sensations, or feelings caused by unknown factors triggering our senses spontaneously.

  • They encompass perceptions and feelings.

• Impressions are more forceful and vivid than ideas, which are pale copies.

• Impressions can be simple (single perceptions) or complex (clusters of perceptions).

  • Simple impressions come from the five senses, like the color perceived when looking at a cloudless sky.

  • Complex impressions are bundles of perceptions, like different sensations of our surroundings.

Ideas

• Ideas are formed when we think about something instead of directly experiencing it.

  • Ideas are less forceful and vivid than impressions, being pale copies of them.

• Ideas can be simple (derived from a simple impression) or complex (composed of other ideas).

  • Simple ideas are copies of simple impressions, such as the idea of 'blue' derived from seeing the sky.

  • Complex ideas consist of other ideas ultimately based on impressions.

The Copy Principle

• Hume uses the principle that an idea requires a prior impression to challenge metaphysics.

• Ideas of substance, cause, or God, which are cornerstones of metaphysical theories (Descartes, Spinoza, Leibniz), lack direct, vivid impressions.

• Hume considers these ideas as fraudulent and suggests they should be discarded as sophistry and illusions.

• The copy principle, or empirical prejudice, is the belief that an idea is a copy of an impression.

Hume’s Fork

• Hume proposes that there are two types of meaningful propositions:

  • Analytic Propositions:

    • Express relations of ideas.

    • Examples: mathematical propositions such as 2 = 2 or the statement that the interior angles of a triangle amount to 180 degrees.

    • Known a priori (independently of experience).

    • Their truth depends on the definitions of the ideas involved.

    • Necessarily true or necessarily false; denial leads to contradiction.

  • Synthetic Propositions:

    • Express matters of fact.

    • Example: "The book is on the desk."

    • Known a posteriori (from experience).

    • Their truth depends on their correspondence with experience.

    • Contingently true or false; denial does not necessarily involve a contradiction.

Hume's Critique of Causality

• Hume defines causality as "an object followed by another… where if the first object had not been, the second had never existed."

• Causality cannot be a relation of ideas since we learn about causes and effects through experience.

• Treating cause and effect as matters of fact is problematic because not all aspects of causality can be traced back to experience.

• Hume finds the ideas in metaphysics, especially causality, obscure and uncertain.

• Causal relations: Relations between objects or events consist of three components:

  • Contiguity (spatial contact): Causal relations must be spatially connected. A must contact B to cause B.

  • Temporal priority (temporal succession): The cause must precede the effect. A must come before B to cause B.

  • Necessary connection: The cause must make the effect happen. A must necessarily cause B to cause B.

• We can observe contiguity and temporal priority but not the necessary connection.

• We infer causation from correlation without experiencing a direct impression of necessary connection.

• Example: Billiard balls – When a cue ball hits a red ball, we see spatial contact and the cue ball's movement before the red ball's movement, but not the necessary communication of movement.

• Hume regards causal relations as "loose and separate" because no necessary connections are experienced.

• The idea of causality lacks components that correspond to any impression, yet it is essential for understanding the world.

The Role of Habit

• We think in terms of causality without a real corresponding impression because it is a cognitive habit.

• When objects and events are repeatedly related in space and time, our minds interpret them as causation.

• This habit of causation becomes fixed in our thinking, even without a vivid impression of necessary connection.

• This cognitive habit leads us to expect events within the chain of associations in our minds.

• This is related to the post hoc ergo propter hoc fallacy: assuming event B caused event A simply because B followed A.

  • This is fallacious because correlation does not equal causation.

• Association and habit, not vivid impressions, underlie the idea of causality.

The Body and Mind Problem

• Descartes: Body and mind are distinct substances (res cogitans and res extensa) connected in the pineal gland.

• Locke: Distinguished between body and mind but admitted their ultimate nature and relation are incomprehensible (an agnostic approach).

• Hume's bundle theory of the self offers insights into the body-mind problem.

The Bundle Theory of The Self

• Hume: The self is not a thing or a res cogitans, it is merely a bundle of impressions.

• We lack a fixed impression of the self.

• We only experience a flux of impressions about ourselves:

  • Impressions of our face in a mirror, the sound of our voice, our body, memories, thoughts, habits, desires, hopes, fears, fantasies, and illusions.

• The term "self" is used to tentatively define this bundle of fluctuating impressions.

• The self as Archimboldo's portrait heads: A collection of items arranged to resemble a head and face.

• Similarly, the self is a mixed assortment of fluctuating feelings and shifting perceptions.

• Hume: Humans are a bundle of different perceptions succeeding each other rapidly in perpetual flux and movement, with no single power of the soul remaining the same even for a moment.

• The idea of self is not derived from any specific or other impression.

• Hume: When looking inward, one always finds a particular perception (heat, cold, light, shade, love, hatred, pain, pleasure) and never catches oneself without a perception, observing only the perception itself. "For my part, when I enter most intimately into what I call myself, I always stumble on some particular perception or other, of heat or cold, light or shade, love or hatred, pain or pleasure. I never can catch myself at any time without a perception, and never can observe anything but the perception."